Products
Diclofenac gel 3% has been approved in many countries since 2010 (Solaraze, generics). In the United States, the gel was registered as early as 2000. Diclofenac is also applied in 1% and 2% concentrations for the treatment of painful and inflammatory conditions (Voltaren Emulgel, generics). This article refers to the three-percent preparation with sodium hyaluronate as an excipient.
Structure and properties
Diclofenac is present in the drug in the form of the salt diclofenac sodium (C14H10Cl2NNaO2 , Mr = 318.1 g/mol) is present, a white to slightly yellowish, crystalline and weakly hygroscopic powder that is only slightly soluble in water. Within the NSAIDs, diclofenac belongs to the arylacetic acid or phenylacetic acid derivatives.
Effects
Diclofenac gel (ATC D11AX18) has analgesic, anti-inflammatory, antitumor, proapoptotic, and antiangiogenic properties. The effects are attributed to inhibition of cyclooxygenase-2 (COX-2). COX-2 is overexpressed in skin lesions and causes inflammation, cell proliferation, it stimulates vascular growth and inhibits apoptosis. By inhibiting COX-2 and prostaglandin synthesis, diclofenac counteracts these processes (Nelson, Rigel, 2009).
Indications
For the topical treatment of actinic keratoses.
Dosage
According to the professional information. The gel is applied locally in the morning and evening and rubbed in lightly. Do not apply over large areas. The treated areas should be consistently protected from sunlight and UV radiation. The duration of therapy is usually 60 to 90 days, i.e. two to three months. Complete healing may not occur until up to 30 days after treatment. The longer treatment (90 days) benefited more patients in clinical trials.
Contraindications
- Hypersensitivity to diclofenac or the gel’s excipients.
- Hypersensitivity to acetylsalicylic acid (aspirin, generic) or other NSAIDs.
- 3rd trimester of pregnancy
- Children (not sufficiently studied)
Full precautions can be found in the drug label.
Interactions
Interactions with sunscreens have not been studied.
Adverse effects
The most common potential adverse effects include local skin reactions such as contact dermatitis, redness, rashes, inflammation, skin irritation, pain, and blistering. Sensory disturbances such as hyperesthesia and localized paresthesias are also common. Discontinue therapy if hypersensitivity reactions or a generalized rash occur.
